Even on the most expensive exercise equipment, despite the lights and gizmos, it's generally impossible to forget that you're still sweating, breathing hard and working nearly every muscle in your body. It's much easier to sit back on the couch and play a video game.

That's why exergaming, which weds video game technology with keeping fit, is poised to become the next gold mine for exercise-minded entrepreneurs. It may not be everywhere yet, but give it time.

In homes, people of all ages are exergaming enough that the California Athletic Trainers' Association recently put out a warning that overdoing it can leave participants with sports-related injuries similar to those experienced by traditional athletes. In gym classes at schools across the nation, stationary bicycles are attached to PlayStation video game consoles, Nintendo Wii game stations are linked to wide-screen TVs, and then there's Dance Dance Revolution, a popular dance video game, which took off in Japan in 1998 and has spread to the rest of the world.

And in some gyms, exergaming equipment isn't merely an offering; it's the focus.

Hitting the GymMike Hansen, 30, and Kevin Bolden, 37, are two pioneers of the pastime, not to mention competitors. Hansen and his business partner, Lenny Lowenstein, 52, own iTech Fitness, headquartered in Denver, which produces exergaming equipment, such as the XR Board that simulates snowboarding, skateboarding and surfing, and licenses its XRKade name to 24 clubs. The gyms, which are aimed at the tween and teen market, let exergamers track how many goals they can score during Goalie Wars or how many knockouts they can rack up during Power Boxing.

Meanwhile, Bolden and his wife, Suzanne, own NexGym, a chain of three fitness centers in Texas, which is also marketing to children. Along with traditional karate and yoga classes, kids can play seven high-tech games, ranging from combat challenges to wall climbing, intended to get them in shape and improve their hand-eye coordination.

At a time when parents are more concerned than ever about their children getting enough exercise, this niche is likely to continue growing. "Childhood obesity is a global phenomenon," says Bolden. "I expect that eventually you will see capabilities in most schools, as well as in convenient locations--malls, shopping centers. Eventually the large fitness facilities will target the same 6-to14-year-old kids [that we target]."

Hansen concurs that the exergaming industry has a lot of room to expand. In 2008, he expects to license XRKades to more than 100 additional gyms and envisions increasingly chasing the adult market as well. "The average video gamer is 30 years old, and 19 percent of the gaming audience is over 50," says Hansen. "The 13 million baby boomers will affect a lot of the thought and process that goes into what we're doing."

Hansen also has seen interest from executives at large companies, eager to get their employees' exercise habits up and their health insurance costs down. Besides, adults want just as badly as children to make exercise fun. "Everyone's so engaged with these games, they don't realize that their heart rate is going up, and that they're burning up calories," says Hansen.

These days, you can easily immerse yourself in a game and forget that you're not actually boxing, skiing or snowboarding. But the potential for virtual adventures goes far beyond sports. Expresso Fitness, which makes a stationary bike that uses virtual reality, already has released Proving Grounds, a bicycle game in which the rider is cycling through a fantasy world. Cyclists chase dragons, score points and can completely forget that they're exercising. And because the stationary bikes are linked to the internet, the games can be updated and retooled through downloads.

The more dragons chased and the more Wii boxing and bowling, the better, says fitness guru John Hayley, president of Hayley Fitness Consulting in Chicago. "The competition of the game allows them to get lost in the moment," he says. "All of the sudden, when the game is over, they find themselves dripping in sweat and can't believe how hard they worked. It gets people to do something, which is far better than the alternative." Concerned parents and gym owners would agree.